A Time for Transcription (Factors)

I’ve been postponing this post for a while, hoping to find the time to expand the analysis, but time seems to elude me at present, so I’ve decided to condense my thoughts and get it out anyway.

In the last few months, my inbox, twitter feed and Chrome tabs have been filling up with papers that focus on transcription factors.

This shouldn’t surprise me, as this is a topic I’m interested in and for which I have some paper alerts. However, there seem to be more more papers than usual, including a growing number of preprint submissions. Some I have covered before on this blog, here and here:

The first paper covers the molecular basis of how (some) transcription factors seem to be working, while the latest two discuss (different) views on the possible moonlighting functions of transcription factors, namely the possibility that spurious binding sites might constrain the evolution of coding regions (hence genetic elements TFs do not have any direct interaction with). Another recent preprints tries to understand a different aspect of TFs evolution: the role triplet expansions might have played.

The attention to role gene expansion plays in protein evolution is gaining momentum, and rightly so: it could very well be a major driving force in functional evolution, in particular in higher eukaryotes where the fidelity of DNA amplification is considerably higher (and hence penalises the occurrence of single point mutations).

However, yet another preprint suggests functional evolution follows a much more complex pathway in which the environment (or more precisely the existence of a fixed selective pressure) works as an evolutionary trap to functional innovation:

Although this shouldn’t surprise in the light of Synthetic Biology, it seems to me as a sort of informed return to the origins: isn’t the yeast two hybrid system the best example of re-engineered transcription factors?